Method of applying abrasives to grinding apparatus.



H. K. HITOHGOCK. METHOD OF APPLYING AB ASIVBS TO GRINDING APPARATUS.

APPLICATION FILID JULY 31,1011

' Patented Mar. 18, 1913.

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METHOD 0F APPLYING ABRASWES T0 GRINDING APPARATUS.

APPLICATION FILED JULY 31,1!HL 1,056, 11 6, Panemm mm. 18 1912,

v H. K. HITOHOOGK. METHOD OF APPLYING -ABRASIVES T0 GRINDING APPARATUS.

LUSGAI 6 APPLICATION FILED JULY 81, 1911.

Patented Mar. 18, 1913.

5 SHEETS" SHEETSv INVENTOR @ZM 7K Maw/4w? H K. HITCHGOOK.

METHOD OF APPLYING ABRASIVES T0 GRINDING APPARATUS.

APPLIOA TION FILED JULY 31,1911.

Patented Mar. 18, 1913.

' 5 BKEBT8SHEET 4 FIG? 88 I04 I05 97 v f 14 w flaw/(1222 HALBERT K. HITCHGQCK, 0F TAR-ENTUM, PENNSYL'ViLNIA.

METHOD OF APPLYING ABRASIVE T0 GRINDING Specification of Letters Patent.

Patented Mar. it. 19% 53;

Application filed July 31, 1911. $eria1 No. 641,484.

To all whom itmay concern Be it known that 1, Hammer K. HITCH coon, a resident of 'larentum, in the county of Allegheny and sensor Pennsylvania, have invented anew and useful Improvement in Methods of Applying Abrasives to Grinding Apparatus, of which the following is a specification.

'Ithis invention relates to a method of handlin grading and applying finely dirided material mixed in water, such as sand or other abrading material for use with grinding machines.

in the griinling and smoothing of material requiring a fine surface such as plate glass, marble and granite, it is desirable after the abrasives have passed between the material to be ground and the runners or rubbing bed, that-the finer particles be sepa rated from the coarser ones and saved to be used in the finishing operation and the coarser particles returned to the grinder to assist in the roughing operations.

The object of the presentinvention is to provide a method of grading and applying such materials wherein thesupply to. and Withdrawal of the material from the grad ing vessel goes on simultaneously, the liner material being held back during the roughing operation for the subsequent smoothing and finishing operation. v

Further objects of the invention are to provide a method whereby the proper ratio of the water to. the sand or other abrading material may be regulated; and providing a method which necessitates simpler and less expensive apparatus than with the methods heretofore suggested, and to provide for starting the finishing operation at any time and bringing it to a speedy close by a series of steps or jumps from a coarse to a fine grade, as will be fully described hereafter. In the accompanying drawings, Figure 1 is a diagrammatic plan view of apparatus tor-carrying out the method; Fig. 2 is a 1 vertical elevation onthe line 22, Fig. 1,

looking in. the direction of the arrows; l ig.

3 is a vertical elevation at right angles to that of Fig. 2 on the line 33, Fig. 2, lookingin the direction of the arrows; Fig. i is a vertical sectional view through the preliminary grading vessel or cone; Fig. is in part a side elevation and in part a vertical section through the sand receiving reser oir or hopper and the grading vessel or cons in connection therewith; Fig. 6.

is in part a vertical section and in part an elevation of the fine sand cone and parts connected thereto; Fig. 7 is a detail view showing the suspending means or the sand cone at right angles to the position seen in Fig. 6, being a section on the line Z-i", Fig. 6; Fig. 8 an enlarged. sectit ital *ltEW of the valve controlling the outlet from the fine sand cone; Fig. 9 is a horizontal section on the line 9--9, Fig. 8', Fig. 10 is a "ertical sectional view through the discharge mechanism from the secondary grading cone; Fig. it is a plan View of the same; Fig. 1.2 is a transverse vertical section on the line 12-l2, Fig. 10; Figs. 13 and it are detail views showing different positions of the valve; Fig. 1-3 is a detail sectional view through one of the troughs and spout connected 'thereto; and Fig. 1G a detail V'lGW shor ing the means for controlling the tlou' of sand from the receiving hopper or reservoir.

In myPatent No. 934,4st1 issued, September 2t. 1905), is described and claimed a certain process for grading tine material in suspension, and in my Patent N 0. 934,612, Sep tember 21, 1909, l: have illustrated and described certain apparatus for grading material, conducting the saute to a grinding apparatus and then returning it for re -gradin T he method of grading or separating the material into grades of the presentap plication has certain general resemblances and follows the same broad principle as the method described in my Patent No. 934,4ell above identified.

In the use of the apparatus illustrated in Patent 34,612, part of the material after being graded is deposited in tanks or bins from which it'is taken to the grinding machines asnecessary ordesired, and upon the return from the grint'lir machines is regraded and again depositeo in such tanks or bins. The material is not continuously in suspension in the liquid in which the grading is etlected, nor is there a continuous cycle, that is, a Withdrawal of material sion is carried on so that the material can be handled at less cost and with less labor than with the apparatus shown in my prior patent.

In the drawings I have illustrated apparatus and herein will describe the mode for grading abrading material and applying. the same for glass grinding operations, but it Will be understood that certain features of the invention are applicable to grading materials and'applying them to other purposes. v

As illustrated, a series of grinding tables 1 each provided with a pair of runners 2 of the usual form, are served from a single preliminary grading vessel or cone indicated at 1, While each of the individual tables is provided with its own individual gradin vessel or cone 5, which is hereinafter esignated the secondary grader to distinguish it from the preliminary grading cone 4. These graders are arranged to regrade the used and new materials so asto retain all of the material-coarser than a given size. The grinding tables 1 may be of any kind or type but are shown of a con Ventional type largely used for grinding plate glass. These are so well understood that specific description thereof is unnecessary. The gutter 6 around each of these tables is connected by cross gutter 7 with the main gutter 8 which conveys the water and used abrading material over a screen 8 to the pit or su'rnp 9 from which it is pumped to the large grading vessel. or cone 4 and. re-graded. The very fine or scununy material from grader 4 escapes through overflow pipe 10 and thence through conduit 11 to the Server, the conduit 11 also can rying the over-flow from the sump 9. The finest grade of sand from grader l escapes through outlet 12 near the top'fof the cone to trough 13, whence it is distributed to the several fine sand cones 14.; one preferably located at each grinding table. The coarser grades of sand from the cone 4 are discharged into the trough 15 and are thereby being properly graded as Will hereinafter be more fully apparent. The fresh abrading material or sand is taken from any suitable source and depos ited in reservoirs or hoppers 17, one located at each grading table. The drawings indicate two modes of delivering the sand into such hoppers; one being by clam shell bucket 18 running on the teller 19 and receiving the supply from sand pile 2O ;1 the other being by a, conduit 21 with branches 22 extending over the hoppers l7 and pro vided with controlling valves 23 and serving to deliver the sand to said hoppers in suspension in water. The surplus or water escapes through overflow pipes 52-1 to conduit 23 which discharges into the main gut ter 8 or other suitable place.

The hopper l7 and the means for di charging the sand therefrom may be .1 various constructions and kinds. but prefer ably is of the form illustrahrd, described and claimed in my application for patentt led concurrently herewith, Serial No. GllA-SZ and in which the sand is removed from the hopper by admitting water into the lower part thereof. As showin the dis marge orifice 26 in the lower end of the hopper is closed by means of the valve 27 and the water is introduced into the lower end of the hopper through pipe 28. lreter ably the admission of the water into the said hopper from below is controlled automatically by the density of the mixture of water apd sand in the grading cone 5. To this end there projects into the said grading cone a hydrometer 30 (see Figs. 3 and 5) guided in a suitable guide 31 and provided near its upper end with adjustable stops 3? l etween which is located the end of lever 3 connected to an ordinary control cock ill in the water supply pipe .58. These parts are so arranged that. when the mixture in the cone 5 is sutliciently dense, the lrvdrometer is elevated and through the stop 39 and lever arm 33 closes valve 34-, thereby stopping the delivery of more sand tocoue 5. When the density of the mixture in the cone is reduced sutliciently, the hydrometer drops and the upper collar 32 contacts with the lever arm 33 and opens the valve I' -l to ad mit, water into the reservoir 1? and restart the delivery of sand from said hopper. in this way an automatic regulation of th density of the mixture in the grauling cone is etlected during the roughing 'or facing operation. Each of cones 5 also receives the coarser portion of the material which comes from the tables, through the regruding cone 4. This material is received from trough 15 which, opposite each of the secondary grading cones 5, is provided with a spout 3Garranged to discharge into the cone :7. .lilCl! of these spouts is controlled by a valve 37 operated by a rope or the like 38 running on sheave 39 connected to the axis on which the valve is mounted, so that the sup ply of sand coming through. troi'igh 1:3 to each one of the grading cones 5 can be controlled at will.

Each of the grading vessels 5 is preterably of the shape shown on the drawing, that is, of inverted cone shape, and is adapted to receive the material mixed with Water from above. The grading preterably effected by maintaining in such cone an upward flow of water whereby the material is divided into various strata pending upon the ratio of thie veight of the diderent particles of mate ial to the resistance altered to emme 1 ing down in the upward current, of we 1 pipe, so that the sand gradually drops down tor, ali as described in my Patent No. until it escapee through the inner open end 3 it above identified. 'ihe upward ilow oi the pipe. ()Olleequelttl), these pipes will of water is provided through the lower end not ordinarily clog, out on the contrary 5 the cone by means of supply pipe it). 1 while no mixture is being withdrawn there- Qhe' action of the upward iiow ot water inv through, they are tilled with nearly clear the conical vessel separates the material into water. In case sand or anything else should various grades. the coarsest being at the clog in any of these pipes front an cause, 1 bottom and successive layers decreasing in have provided the following arrangement coarser ss toward the top. The very fine or for clearing the stiltltli The outer ends of the at n' material. as well as surplus water withdrawal pipes are connected to a suitable :a through overflow pipe in. which conchamber (it) which is supplied with water 1:2 with the gutter ti of the grinding under pressure through pipe (it. From chamber there are ports leadir into the Q by t S r t l ithd the outer ends of all of the withdrawal pipes, $0 grades from the grading Vessel, there are each of which ports is controlled by a check projected into said vessel 21 series of pipes valve 6:2 controlled l v spring 63 to nor- 1 2, and 4 1-, in vnumber depending upon mally clmse communication from chainher (30 the number of grades to be separately with to the end of he withdrawal pipe. 'lo undrzltvlg, The lower inner ends of these pipes seat the valve (32 and open communication are at diti'erent heights in the grading vesfrom chamber (30 lo the withdrawal pipe, gel and each ends approgin tel i the the tiap valve 4-? is pri'ivided with a projecstrata or zone of the ti ul grade hi h tron or prong U-i of sufficient length to 0011- it. is desired to withdraw"through that; pip tact with the check valve 69 and lift it from if these pipesextend th h th ide f in stat when the ruhlwriacuig or packing f b i ]1 h Same level d 5815 compressed. The nornial condition of @utjgyf gr ds bend dgwnwa dly sognewhat tilt (lOHttl Vtll\'t- BllOd'll ill 10 Will] tilt: "will in 2 a d d ll are a]:- projection or prong (i-t lmrel contacting 'ed to (liecharge into the spout 4-5 which ith valve 672 hut without lilting; the same ghuyggg nigt the trgugh 46 which fitll'i'l ll}; seat. SllOllltl. 'fOt' H11 ttlti fi, (H163 Of over the grinding table,'l)i'efemb1y vlllmi'mml PP b90011? L eed. the '1 [h funnel-5 as gumvn d i d rope 3? pulled upon in such a direction as ttmiiecharge theinixture of sand and i0 l'mYihiV COmPTLSS the I m! 1 as i onto the tahle, The diechaite ends of ti P pipers are controlled by independent i lift the valveGQ from its' s-eat. vi ater 103 vali i th v lv beintr gm d under pressure from the supply pipe (3 now j 47 g d 49, (1 j 1Q 11 and ilows inwardl and dmvnwardlv tl'irough the 47 i giftfujfid t a t b j i -f 543 ch 'ed pip, and washes out of the same the 1 ith ti sheave 51; th cu 'Q'Hlfj material. Fig. 1% illustrates the I i cmmPL-{m} to ga e 52 hi h position-oi the valve when open to permit tends through hollow h 50 d n'iaterial to he withdrawn from the cone 5.

'ided with operating e W 53; nd th Each of the v: lves t, 48 and 49 is inde- .5) 5 Swarm m'g g fi; 5. 'gyidgd ith pendentlv eontrolled and this permits the 1g sheave Each f th s r gwitlwlrawal oi the several grades separately sheaves is weighted, as at 56, so that and independently and to an e :tent: or do (dosed the weight keeps the valve efree. in other words, it; is not. ccessa'ry to a 'ainst the head or pressur of t e withdraw all of the a dee lying between 1 re in the tank, and when opened this any two planes hetero taking; out or beginwe jnt iteepe the valve open. Each sheave nine; to take out the upper or finer grade. provided with a rope or similar device 57 This enahlee the finishing operation to he for operating the same. brought to a speedy eonclusioi'i. whereas with Each of the valves is provided with a soft. the prior apparatus where the dii' ferent packing or face 58 adapted to seat against grades. were withdrawn tihrough a common the open end of the pipe and close the same. outlet. it was necessary to entirely withdraw The mixture of sand and water is forced out all oi the grades before the finest could he mg of the pipes when they are openedby the taken out.

presaure of the head in the cone 5. but this When the material in any layer is; withgncssure he not so great but. that. when the drawn that mimediatelv above drops down valve closes the end of the pipe the outflow to take thentaceof the withdra *n layer. and

egxned the. flow through the open pipe is pipe the material being withdrawn tnrad set an. is soon as the valve is again closed ually becomes. finer and finer. The with the W611i which 18 in the pipe drops out of draw-a1throughanyone pipe can he stopped the $111118 haul-z into the com.- 5, due to the fact. whenever desired, and a rat there 15 no upward .tiu of water in the pipes opened. This e: a...

. innnediately ceases, but as soon as a valve it, the Withdra 'al continues through any one various grades. With the coarser grades asmall ratio of water can profitably-be used,

While with the finer grades the ratio of Water preferably should increase.

ent. grades was secured'loy means of afloat located in a suitable vessel and controlling the valve which controlled the amount of Water entering the grading cone. In the apparatus illustrated in this application, this regulation-is automatically eifected without such float'and regulating valve by properly prop'ortioning the shape or lines of cone 5 and properly locating the points of withdrawa'l of the different grades therefrom, that'is to say,- the dilferent heights at which the withdrawal pipes terminate in said cone.

By properly designingthe shape of the cone and having the; several withdrawal pipes projecting dox'vn lDflZO' the cone to exactly the right points, I am enabled to automatically and properly regulate the ratio of Water to the sand, so as to secure the increasing ratio of water to the sand for the finer grades.

. This considerably simplifies the apparatus over that illustrated in my prior patents.

The large or preliminary grading cone 4:. receives the mixture of water and sand as it comes back from the tables from the sump or pit'.9. This mixture is discharged upwardly into the said cone through its lower end by means of a rotary pump 66, shown as of the centrifugal'type having connected to its inlet a-conduit 67 which dips down in the pit 9 and having its discharge arranged to project the mixture up into cone 4. This pump can be operated in any suitable way, such for instance as by the electric motor 68. The cone 4; in its general construction is similar to the cone 5 and has the same general arrangement of pipes and controlling valves as already described for withdrawing the material therefrom and its action is preferably the same as thatydcscribed in my Patent No. 9343M in connection with Fig. 3." .As shown, there are in this cone four discharge pipes 70, 71', 72 and 73 forwithdraw-- ing the coarser gradesof material and an upper discharge p1pe'12 for witl'ulrauung .the finest grade and delivering the some to the tough l3.which conveys it. to the fine In my patent hereinbefore described, this regulation of. the ratio at water to the sand for the difierof those are again mixed, in trough 15 and are re-graded in thecones 5. The purpose of taking out of the cone 4-. the several independent grades through pipes 79,

ZL'flZ-and 73 is to remove as quickly as possihle all of the coarser. material and thus in "sure'havingthe uppermost grade which as capes through outlet 12, very carefully selected. -a.-'cons equence,-a very careful grading or selection of the upper or tine material is secured. .Each ofthe fine-sand cones 1d, theretore, receives its supply from the top stratum of the preliminary re-grading cone .4. The sand from these fine sand cones is withdrawn onlyat the end of the rinding operation so as to efi'ect the final or linishing grinding. Each of these conesis arranged to automatically control the delivery of the fine sand thereinto, and to discharge said sand through an outlet 80 in its bottom directly into the trough 4:6.

For the purpose of regulating the supply of sand into the cone M, the following ar rangement is provided :The cone is susended by means of a bail or stirrup 81. roni the short end of lever 82 fulcrumod at 83, and having on its long arm adjustable counter weights 84. The short arm of the lever has connected thereto a link 8;} attached to the stem 86 of a valve Sflwbich controls the discharge spout 88 from trough 13. Until the mixture in the cone 14tacquires the proper density, the cone together with connected parts, is overbalanccd by the weights-84, in which condition the weights 84 are depressed from the position shown in Fig. 6. The S l1'10Il; end of lever 82 is elevated and valve 87 ifted to open the inlet to discharge spout 88 so that the mixture of fine sand and water flows into the cone 14-. As soon as the mixture in the cone lat has reached the desired density, it overbalunces the counter weights 84, lifts the"latter and depresses the short end of lever 82, thereby forcing valve 87 downwardly to close the inlet to spout 88 and shutting oil the sup ply of fine sand and water to the cone 1-1.- It is understood, of course, that the trough 13 is stationary. 1 When the cone 14- drops as described, the lever 82 islocked in the position shown in Fig. 6 by means of a dog 90 provided with a lug or shoulder 91 adapted to engage a lug )2 on the lever and prevent counter weights .84. from dropping until dog 90 is released, which can be done by means 015 the rope93 attached to an .arm 94 on the said dog. A spring 95 normally holds the dog" against the st-o 92. This holds the velte 87 closed until the line sand cone has -lift the cone and valve 87.

The fine sand the cone M. is graded the top so that When Withdrawn through the bottom discharge orifice, the finishing sand gradually becomes finer and finer.

'lhe discharge orifice 80 of the fine sand cone is controlled. by a valve 100 which is seemed to a stem 101 guided in the lower end oi. tube 97, said stem being fluted or grooves, as at 102, so that it cannot stop the flow of Water fron'l the pipe 92. Connected to the valve stem 101 is a rod 103, extending upwardly above the'cone and connected to the one end of lever fulcrumed at 105, and having connected to its opposite end an operating rod 106. .By pulling down on the latter, the valve 101 is lifted to open the dis urge orifice, and the fine sand and Water then escape from he cone 14.

in carrying out tlrx: method, the sand is deposited in hopper 1' washed out of the same by opening valv" 34, and passes, mixed with water, into the ,rading tank or cone 5 where it meets an upward current of Water of gradually diminishing velocity toward the topmnd settles down in the Water in said tank until it reaches a state of equilibrium, which depends upon the size and physical characteristics of the particles of sand, so t. they are thereby divided or separated into several grades or sizes. The grades are an helrawn and conducted. separately to the grinding; table by opening the appropriate v 4-8 or 49, controlling the several lraivai from said cone. The sand or from the grinding table escapes u?" and aasses then to sump 9, ding ta is more or less of the erized to a degree of fineness ".citates it for further service as The sand mixed with Water, is ump or pit 9 and discharged he preliminary grading tank :ream of Water carrying the is cone gradually diminishes unrdly and the different para sock their strata of equilib- Lille as in. the tank or cone 5, and w r -by separated into a series of axes. The very fine particles, too ,3 be of usrn scum, dirt and other im- 1 Wash out through the overthnvlO c The coarser grades of matecs 70, 71, 72 and w. being ding tank 5, While the unset osited in the finishing oration.

mi). from this tank throu hcone 14, to be withdrawn therefrom Whenever the grinding operation has reached the stage for the final or finishing operation. During the coarse grinding or roughing, the

.coarser grades (or even the coarsest grade' only) are taken from the vessel or cone 5 to the table, and simultaneously the material from all the grades, except the finest in cone 4, are returned to the cone 5 for regrading', and fresh material is also supplied to the cone from the reservoir 17, this sup- "ply being controlled by the, density of the mixture in the cone 5.

\Vhen the roughing or facing operation is substantially completed, the supply of material to the cone 5 is cut off by closing valves 34? and 37. The operation then continues with the withdrawal from the cone 5 of the several grades in succession, or by steps or jumps, as above described and to the extent desired or necessary, the material becoming finer and finer, and after this has been further Withdrawal from cone 5 ceases and the finishing or smoothing is completed by withdrawing entirely from the fine sand cone 14, when, again, the material With drawn gradually increases in fineness from the bottom to the top.

During the rough grinding there is a continuous circulation of the abrading material in water; from cone 5 to the grinding table, thence to sump 9, thence into cone 4, and thence by trough back to cone 5. The portion of material too line for further use is washed by the overflow into the sewer and the finest usable grade is conveyed to the fine sand cone 14 for the finishing op- Simultaneously therewith fresh material is being added to cone 5 to make up for the fine material Washed into the sewer and that-taken to the fine sand cone. During the roughing or facing operation when. the sand is being admitted into the tank Strom the hopper 17 and the trough 15, it is possible to shut oll'theinflow of water through the pipe 40, in which case the heavier particles of sand on account of their greater weight in proportion to their re sistance to the water, fall rapidly to the bottom of the cone and are withdrawn through pipe 42. The finer particles ofsand, requiring a much longer time to fall down into the liquid, have a tendency to remain in suspension higher in the cone, and as long as the coarse sand is Withdrawn through the pipe 42 as rapidly it is accumulated in the bottom of the cone 5. fairly satisfactory results may he obtained, but I prefer to in trod'uce through the pipe 40 enough'water to more than equal the volume of mixture being Wltl'KllflWll through pipe 42 which causes a continuous upward flow of Water in carried far enough,

the cone 5 and prevents any of the finer particles of sand coming down and being mixed with the coarser grades which. are be.-

ing withdrawn through the pipe 42, as would apparatus.

be the case were the water shut oil from the pipe d0 or when the volume of water introduced through the pipe act is less than-the volume oi water being discharged through the pipe 42. v

Bythe methoddescribed, there is a continuous and uninterrupted cycle of the abrading material, constantly or practicallycnstantly, in a state of-suspension, orlat least mixed with water; storage place is nec essary or required and, therefore, the labor of handling is reduced practically to a minimum, and the apparatus is of less size and less expensive than where storage must be provided for. The apparatus is so designed that the graded material is withdrawn from the grading tanks and is discharged into said tanks simultaneously, 2'. e. both operations going on at the same time, but with;

out interfering with the accuracy of the grading This does away with the necessity of storage places or tanks, and permits the use of very much smaller and less expensive tanks or cones than with my What claim is 1. The method of applying abrasives to grinding and smoothing mechanism, which consists in separating the material mixed with a liquid in a suitable vcssel, or tank into different grades, withdrawing said grades separately and in any desired sequence from said vessel, .conducting the same directly to the grinding mechanism, and returning the same to the grading vesselwhile still m xed with the liquid and introducing the same into the 'to'por said vessel or tank and re grading the same. t H

2. 'lhemethod'of applying abrasives to grinding and smoothing mechanism, which consists in separating the material mixed with a liquid in a suitable vessel or tank into different grades, withdrawing said grades separately and in any desired sequence from said vessel, conducting the same directly to the grindinginechanism,and returning the same to the grading vessel while still mixed with the liquid and introducing the same into the top of said vessel ortank and regrading the same, said grading, regrading and circulation :being carried on in an uninterrupted cycle with the materialcon stantly mixed with the liquid.

The method of applying abrasives to grinding and smoothing mechanism, which consists in introducing'the material mixed with water intothe top of a suitable vessel or tank, eliminating the surplus water V therewith withdrawing the. coarser material.

and some of the finer material-from the upper portion of the tank and simultaneously from near-the; bottom of the-tank and cond'upting thelsame 'directlyfto the grinding mechanism, and rsconducting the usedmat:

' from the coarser material.

prior form of per portion of the tank and simultaheoilal rial from the grinding. mechanism and again introducing itinto the top of said tank or vessel.

ii The 'mlh'hd el applying abrasives to grinding and smoothing mechanism. which consists in introducing the material mixed with water into the top of a suitable vessel or tank, eliminating the surplus water and some of the finer material from the up per-portion of the tank and simultaneously i therewith withdrawing the coarser material from near the bottom of the tank and conducting the same directly to the grinding mechanism, reconducting the used material from the grinding mechanism and again in troducing it into the top of saidtank; or vessel, and again. separating the finer material 5. The method of applying abrasives to grinding and smoothing mechanism, which consists in introdilcing the material mined with water into the top of a suitublelrssel' or tank, eliminating the surplus'wiiter and some of the finer material fromthe-luuy therewith withdrawing the coarser material from near the bottom of the tank and conducting the same directly to the grinding ing the same in a state of suspension to the grinding -mechanism, regrading the used material in a separate vessel,vwithdraw1ng the finer grades in said vessel from circulation, and conducting the several coarser grades from said vessel to the first named vessel and regrading the same, said grading, preliminary grading, regra-ding and circulation being carried on in an uninterrupted cycle-with the material constantly mixed with the liquid.

7. The method of applying abrasives m grinding and smoothing mechanism, which consists in: conducting the material, mixed with a liquid boa vessel and therein separating the same,,into various. grades, with drawing said grades from said vessel separately and conducting the same directly-to the grinding mechanism, conducting the used 'materialto. a separate vessel and therein regrading' the same, withdrawing the several grades separately from said vessel,

withdrawing the finer grade in .said vessel from circulation, and conducting the-several coarserfgrades-collectively from said vessel to the first named vessel and therein regra ling the same, said grading, regrading and circulation being carried on in an unli'iterrnpted cycle with the material constantly mixed with the liquid. i

8. The method of applying abr 'ives to grinding andsn'ioothing mechanis which consists in coni'lueting the same'to a suitable vessel and therein separating the same into ditl'erent grades, simultaneously therewith witlnlrawing the grade separately. from said vessel'and conducting the same directly toythe grinding mechanism, conducting the used material from the grinding mechanism to a separate vessel and therein separating the same into various grades simultaneously with the introduction of thematerial into said vessel, Withdrawing the same therefrom, and reconducting all of the material below a certain size to the first named vessel. 9. The method of applying abrasives to grinding and smoothing mechanism, which consists in conducting the same to a suitable vessel and therein separating the same into difi'erent grades, simultaneously therewith withdrawing the grades sepai ately from said vessel and conducting the same directly to the grinding mechanism, conducting the used material from the grinding mechanism to a separate vessel and therein separating the same intovarious grades simultaneously with the introduction of the material into said vessel, withdrawing the same there-.

from, and reconduct-ing all of the material below a certain size to the first named vessel,

said grading, preliminary grading, regrading and circulation being earried on in an uninterrupted cycle withthe material constantlyamii'red with the liquid.

'10. The method of grading" and applying abrading material, consisting-i l separating the material mixed with a liqu ll in a suitable vessel 'or tank into difi'erent grades, con ductingthe graded material'to a grinding machine, regrading the used material in a separate vessel, withdrawing the several grades separately 'from said vessel Withdrawing the .finer grade in said vessel from the circulation, conducting the several coarser grades from said vessel to theifirst named vessel, and therein regrading the same.

11. The methodiof gradingand applying ahracling material, consistingi'n separating the material mixed with a liquid in a suitable vessel or tank into different grades,

conducting the graded material to a grinding machine, regrading the used material in a separate vessel, withdrawing the several grades separately from said vessel, with;

drawing the finer grade in-said vessel from the circulation, conducting the several coarser grades from said vessel to the first named vessel, and therein regrading the same, such grading, regrading and circulation being carried on with the material constantly in circulation mixed in liquid.

12. The method of applying abrasives to grinding mechanism,consisting in introducing the abrasive mixed with water into the top of a tank having downwardly converging sides, eliminating the surplus water and some of the finer material from the upper portion of the tank, and simultaneously therewith withdrznving the coarser material from near the bottom of the tank and conducting the same directly to the grinding mechanism.

13. The method of applying abrasives togrinding mechanism, which consists in in troducing the abrasive mixed with water into the top of a tank having downwardly converging sides, eliminating the surplus water and some of the finer material'from the upper portion of the tank, and simultaneo'usly therewith and while holding the abrasive constantly mixed with Water with drawing the coarser material from near the bottom of. the tank and conducting the sametl directly to the grinding mechanism.

14. The method of applying abrasives to grinding mechanism, consisting in introducing the abrasive mixed with water into the top of a tank having downwardly converging sides, eliminating the surplus water and some of the finer material from, theupper portion of the tank, withdrawing the coarser material from near the bottom of the tank conducting the same dircctlyto the grinding mechanism, and returning the abrasive material from the grinding mechanis ato-the tank, said operations going on simultaneously.

15. The method of applying abrasives to grinding mechanism, consisting in introducing the abrasive material mixed with water.

into the top of a tank having downwardly converging sides, eliminating the surplus water and some of the finer material from the upper portion of the tank, and simultaneously therewith withdrawing material directly to the grinding mechanism from any one of'various levels in the tank.

In testimony whereof, I have hereunto set my hand. Y

HALBERT K. HITCHCOCK.

\Vitnesses: i

MABEL S. Tz-ronrson, W. (l. LYON. 

